Survival Instinct
by JeVeuxReves
Summary: He's gotten through the walls she had build around her, pulled her out of certain death more times than she cares to count, and very recently, gotten her through a harrowing interrogation. She just needs him to help her get through this too. My own take on the missing scene from In The Belly of the Beast.


**Author's Note: So I just watched this episode, and I figured I would throw in my take on what happened. Let me know how I did.**

She stays where she is when Elena melts away into the darkness, kneeling in the detritus at the feet of her would-be executioner. She can't bring herself to believe that it's not a trick, and her ears strain to find footsteps, the snap of a twig nearby. The eerie silence, pierced only by the soft rattling sound that emerges from her own chest, is infinitely more terrifying. She is trained to be wary when someone acts out of the realm of her expectations, and she can't think of a single reason for Vulcan Simmons to spare her life, especially now that she can identify him as Lazarus.

Unless he's not. Simmons could be a decoy: Elena hadn't said 'Simmons', she had said _Lazarus_. The theory has the ring of truth to it, makes sense in some way she can't make sense of. All the pieces are there. She's too foggy to see the whole puzzle, but she knows that it's hidden away somewhere inside her waterlogged brain.

She spends a full minute trying to dig it out of her mind before she reminds herself that it doesn't matter just now. Simmons is going to scrub the compound, and she's in no condition to collect the evidence she needs to mount a case. She needs to let him go for now because she's not out of the woods yet, and won't be until she's out of _these_ woods and in police custody. The assassin had saved her from getting shot, but there's a new threat that she has to deal with. She's soaked to the skin and the temperature is dropping dangerously low, sapping her strength – and she has precious little left to lose. She's alone and cold, half-drowned, worn out, tied up, and on top of all of that, she thinks she did something to her shoulder during her tumble into this gully, and she _knows_ she sprained her ankle because she can feel the rope around it biting into her swollen flesh. Exhaustion is pressing in on her, lingering in the darkness at the edge of her vision and she knows that if she gives in to it, she will never get up again, knows it in the churning of her stomach and the icy grip of surrender in her bones.

Moving is the very last thing in this world that she wants to do, but it's move or die. Eventually someone is going to realize that her companion hasn't returned, and she can't be here when they find the body. She shuffles closer to the dead man, her movements awkward and inhibited. Pain lances through her shoulder, drawing out a gasp that sends shards of glass shooting through her chest. It turns her vision white and doubles her over, pressing her face into the mulch of damp soil and twigs and decomposing leaves. The cut on her forehead burns at the contact, and it's the addition of this audacious little sting that does what hours of interrogation could not: break her. She chokes on a sob, coughs up fire instead, and it leaves her dazed, breathing in short little pants that rustle the leaves an inch beneath her lips, curled in on herself in a position that is more a mockery of prayer than anything else. She tries very hard not to feel as thoroughly defeated as she knows she is when she realizes that the pain has robbed her of even her ability to give in to the turmoil roiling through her.

Sitting up takes everything she has left in her, and she overbalances, falling onto her wounded shoulder. It takes the breath from her battered lungs with a pitiful wheeze that doesn't have the conviction to be a scream.

She has no idea how long she lays there, her half-lidded eyes trained on the face of the dead man. In the darkness, she can see his face in high relief, take in the planes of his slack jaw, the slope of his nose. The moonlight filters through the trees and reflects in his sightless eyes and she stares dully at an example of her own future. She survives a one-man firing squad, saved at the last second, only to freeze to death beside him. Situational irony. Castle would have a field day.

She only hopes that he'll give Nikki Heat a better ending. She was so looking forward to their happily ever after. She thinks about all the times she's promised him _always_ , but will never get to promise him forever, never get to stand in front of him and let him put his ring on her finger and claim her as his. She thinks of all the time they'll never have, and then looks back on all the time they wasted, and when she closes her eyes against the tears, she can see him like he's right there with her: that toothy, crooked smile she loves all the more because he's self-conscious about it, his blue eyes, pupils blown wide when she arches her back over him, the way his brow furrows in those few-and-far-between moments when he's actually serious, the way she kissed him and promised him _later_ just before she headed off to the precinct ten hours and a lifetime ago.

Her teeth make a quiet grinding sound when she presses them together, feels the pressure in her jaw and the pain in her abused body when she pushes herself up. With her hands tied behind her back like they are, she has to frisk the body blind, but she doesn't need to see the phone she finds in his pocket to dial. She knows this number like she knows her own name, and she lets herself crash back down beside the receiver. "Hello?"

"Castle." She sobs his name and it makes her cough again, a wet, rattling sound that steals her breath.

"Kate?" His voice is flooded with relief. "Beckett! It's Beckett!" She can hear the precinct in the background, a bustle of noise and activity. What she wouldn't give to be there.

"Castle, I can't stay here." She tells him, her words tumbling out of her mouth in a jumble because her lips have gone too numb to distinguish between them. "They're going to come looking for him and when they find him, they're going to come looking for me." The explanation probably makes no sense to him, but he's her partner, the one person she trusts to know what to do when she doesn't.

He doesn't let her down. "Okay. Beckett, I need you to get out of there. Find a place to hide and wait. The Scarsdale police are on their way, and we're right behind them. We're an hour out."

She hears an engine revving and Javi's gruff voice. "Thirty minutes." He corrects, and she feels a rush of affection for him, and something so much less altruistic. Darkness is encroaching on her vision, her head is hazy and she feels sluggish all over.

"I don't think I can." She knows her words come out slurred because his come back razor sharp.

"That's not good enough, Kate." He tells her, his voice calm but insistent. "You can. I've seen you in action. I know you can."

"I can't bring the phone." She says, tugging uselessly at her bound wrists to demonstrate her point. "There wasn't a knife on him."

"Then leave the phone, but you need to go. Can you do that for me?"

"For you." She agrees. "Castle, hurry." Getting to her feet is the hardest thing she's ever done in her life. Her muscles protest, try to betray her with every turn as she rocks onto her knees and back onto the balls of her feet. Her swollen ankle sends a jolt of agony up her calf and she defies it, the muscles in her thighs quivering as she forces them to work, push her onto her feet. The effort leaves her panting, and she limps along the gully, her ankle threatening to give out with every step.

She stumbles a dozen times in the darkness, only barely regaining her balance each time, and falls still at every sound, her heart beating a staccato rhythm in her throat. Each step is agony: her body longs to shut down, she's trembling all over, whether from the cold or from the exertion, she doesn't know. She sets her jaw and persists. She has found a reserve of strength, dragged it out of the recesses of her soul and battled it into submission. She made Castle a promise, and she will be damned if she's going to break it. She keeps moving, hoping that it will stay the cold that's stiffening her shirt into ice and forming a crystalline halo in her hair.

She reminds herself that the freezer was colder, and she survived that, but a soft, sinister voice in the back of her head points out that in the freezer, she had Castle, and she is alone now. There are no sirens in the distance, no rescuers crashing through the underbrush, just her, all alone and accompanied only by the sound of her half-drowned lungs rattling like death itself and the sound of her heartbeat pounding in her own ears.

And that heartbeat is getting weaker.

She trips over a fallen trunk, bouncing her shin off the bark, and she knows that there is no getting up again. Her arms and hands are numb and her legs aren't responding to the orders she's giving them. She thinks of Castle, thinks that thirty minutes was just a little too long, and then she thinks nothing at all.

 _Dear Rick,_

 _I don't know how much time I have, even to write this letter._

 _What I do know is that I'm in this, and the only way I'm gonna make it out alive is to see this through._

The Scarsdale police have already found the body and the phone by the time they arrive, and they join the search with abandon. Castle finds her, drawn by the same sense of magnetism that has brought them together over the years. Her wet hair and black turtleneck are impossibly dark against the stark whiteness of her skin, and it sends his stomach into his toes until he finds the thrum of her pulse in her icy neck, weak but undeniably there.

 _I'm sure everyone is looking for me, and if they figure out I was here, CSU's gonna search this house._

The diagnosis is mild hypothermia, a sprained ankle, a dislocated shoulder, and half a dozen scrapes and bruises. Infuriating woman that she is, she refuses to let them take her to the hospital, refuses to leave the manor as long as there's a chance they'll find something to connect to Vulcan Simmons. Even weak as a kitten, she is still enough of a force to be reckoned with that no one dares to challenge her.

 _They're gonna look for blood, and they will find it, which will lead them to this letter._

He's her fiance, and so he sits with her in the back of Espo's cruiser once the EMTs let her go, lets her huddle into his side and leech his body heat. She finally sleeps with her head pillowed on his shoulder. He's her partner too, so he backs up her decision to stay, even when Ryan offers to drive them back to the precinct before she wakes up. He wants Simmons caught as much as she does, wants to see the bastard in handcuffs, locked away in a cell. He passes the time writing in his head, creating a character he names Varick Seavers and killing him over and over again in every way he can imagine. He learns that he is a very imaginative person, but possibly not a very good one.

 _Babe, it's your letter, and I hope you never have to read this – that I can tell you all of these things in person, but if something happens and I don't make it,_

"Mr. Castle?" He looks up at the office, a young uni he doesn't know, and holds a finger to his lips when Beckett stirs at his side, snuggles closer into his warmth and lets out a quiet little sigh against his chest. The cop nods his understanding and speaks in a low voice. "We found this in an air duct inside. I think it's for you." Castle accept the slip of paper, unfolds it carefully so he doesn't jostle her, his brow furrowing as he reads.

 _I need you to know that our partnership, our relationship, is the greatest thing that has ever happened to me. You're an amazing man, and I love you with all of my heart._

"That was just in case I died." Her voice, hoarse and scratchy, startles him. "You weren't supposed to see it otherwise." She clears her throat a few times. He rubs his palm over her back beneath the blanket she's cocooned in and presses a kiss to her crown through her damp hair.

"That's okay." He soothes. "You can tell me again when we get married. And the day after that, and the day after that, and the da-" She silences him with a kiss, frames his face in her chilled hands and rests her forehead against his, a smile tugging at the corners of her mouth.

" _Always_."


End file.
